/*
 * Copyright 2013 Blaz Solar
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.sunday.common.widgets;

import android.annotation.TargetApi;
import android.content.Context;
import android.content.res.TypedArray;
import android.os.Build;
import android.util.AttributeSet;
import android.view.Gravity;
import android.view.View;
import android.view.ViewGroup;

import com.sunday.common.R;

import java.util.ArrayList;
import java.util.List;

/**
 * FlowLayout will arrange child elements horizontally one next to another. If there is not enough
 * space for next view new line will be added.
 *
 * User: Blaz Solar
 * Date: 5/6/13
 * Time: 8:17 PM
 */
@TargetApi(Build.VERSION_CODES.ICE_CREAM_SANDWICH)
public class FlowLayout extends ViewGroup {

	private int mGravity = (isIcs() ? Gravity.START : Gravity.LEFT) | Gravity.TOP;

    private final List<List<View>> mLines = new ArrayList<List<View>>();
    private final List<Integer> mLineHeights = new ArrayList<Integer>();
    private final List<Integer> mLineMargins = new ArrayList<Integer>();

	public FlowLayout(Context context) {
		this(context, null);
	}

	public FlowLayout(Context context, AttributeSet attrs) {
		this(context, attrs, 0);
	}

	public FlowLayout(Context context, AttributeSet attrs, int defStyle) {
		super(context, attrs, defStyle);

		TypedArray a = context.obtainStyledAttributes(attrs,
				R.styleable.FlowLayout, defStyle, 0);

        try {
            int index = a.getInt(R.styleable.FlowLayout_android_gravity, -1);
            if(index > 0) {
                setGravity(index);
            }
        } finally {
            a.recycle();
        }

	}

    /**
     * {@inheritDoc}
     */
    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);

        int sizeWidth = MeasureSpec.getSize(widthMeasureSpec) - getPaddingLeft() - getPaddingRight();
        int sizeHeight = MeasureSpec.getSize(heightMeasureSpec);

        int modeWidth = MeasureSpec.getMode(widthMeasureSpec);
        int modeHeight = MeasureSpec.getMode(heightMeasureSpec);

        int width = 0;
        int height = getPaddingTop() + getPaddingBottom();

        int lineWidth = 0;
        int lineHeight = 0;

        int childCount = getChildCount();

        for(int i = 0; i < childCount; i++) {

            View child = getChildAt(i);
            boolean lastChild = i == childCount - 1;

            if(child.getVisibility() == View.GONE) {

                if(lastChild) {
                    width = Math.max(width, lineWidth);
                    height += lineHeight;
                }

                continue;
            }

            measureChildWithMargins(child, widthMeasureSpec, lineWidth, heightMeasureSpec, height);

            LayoutParams lp = (LayoutParams) child.getLayoutParams();

            int childWidthMode = MeasureSpec.AT_MOST;
            int childWidthSize = sizeWidth;

            int childHeightMode = MeasureSpec.AT_MOST;
            int childHeightSize = sizeHeight;

            if(lp.width == LayoutParams.MATCH_PARENT) {
                childWidthMode = MeasureSpec.EXACTLY    ;
                childWidthSize -= lp.leftMargin + lp.rightMargin;
            } else if(lp.width >= 0) {
                childWidthMode = MeasureSpec.EXACTLY;
                childWidthSize = lp.width;
            }

            if(lp.height >= 0) {
                childHeightMode = MeasureSpec.EXACTLY;
                childHeightSize = lp.height;
            } else if (modeHeight == MeasureSpec.UNSPECIFIED) {
                childHeightMode = MeasureSpec.UNSPECIFIED;
                childHeightSize = 0;
            }

            child.measure(
                    MeasureSpec.makeMeasureSpec(childWidthSize, childWidthMode),
                    MeasureSpec.makeMeasureSpec(childHeightSize, childHeightMode)
            );

            int childWidth = child.getMeasuredWidth() + lp.leftMargin + lp.rightMargin;

            if(lineWidth + childWidth > sizeWidth) {

                width = Math.max(width, lineWidth);
                lineWidth = childWidth;

                height += lineHeight;
                lineHeight = child.getMeasuredHeight() + lp.topMargin + lp.bottomMargin;

            } else {
                lineWidth += childWidth;
                lineHeight = Math.max(lineHeight, child.getMeasuredHeight() + lp.topMargin + lp.bottomMargin);
            }

            if(lastChild) {
                width = Math.max(width, lineWidth);
                height += lineHeight;
            }

        }

        width += getPaddingLeft() + getPaddingRight();

        setMeasuredDimension(
                (modeWidth == MeasureSpec.EXACTLY) ? sizeWidth : width,
                (modeHeight == MeasureSpec.EXACTLY) ? sizeHeight : height);
    }

    /**
     * {@inheritDoc}
     */
	@Override
	protected void onLayout(boolean changed, int l, int t, int r, int b) {

		mLines.clear();
        mLineHeights.clear();
        mLineMargins.clear();

		int width = getWidth();
		int height = getHeight();

		int linesSum = getPaddingTop();

		int lineWidth = 0;
		int lineHeight = 0;
		List<View> lineViews = new ArrayList<View>();

		float horizontalGravityFactor;
		switch ((mGravity & Gravity.HORIZONTAL_GRAVITY_MASK)) {
			case Gravity.LEFT:
			default:
                horizontalGravityFactor = 0;
				break;
			case Gravity.CENTER_HORIZONTAL:
				horizontalGravityFactor = .5f;
				break;
			case Gravity.RIGHT:
				horizontalGravityFactor = 1;
				break;
		}

		for(int i = 0; i < getChildCount(); i++) {

			View child = getChildAt(i);

			if(child.getVisibility() == View.GONE) {
				continue;
			}

			LayoutParams lp = (LayoutParams) child.getLayoutParams();

			int childWidth = child.getMeasuredWidth() + lp.leftMargin + lp.rightMargin;
			int childHeight = child.getMeasuredHeight() + lp.bottomMargin + lp.topMargin;

			if(lineWidth + childWidth > width) {
				mLineHeights.add(lineHeight);
				mLines.add(lineViews);
				mLineMargins.add((int) ((width - lineWidth) * horizontalGravityFactor) + getPaddingLeft());

				linesSum += lineHeight;

				lineHeight = 0;
				lineWidth = 0;
				lineViews = new ArrayList<View>();
			}

			lineWidth += childWidth;
			lineHeight = Math.max(lineHeight, childHeight);
			lineViews.add(child);
		}

		mLineHeights.add(lineHeight);
		mLines.add(lineViews);
		mLineMargins.add((int) ((width - lineWidth) * horizontalGravityFactor) + getPaddingLeft());

		linesSum += lineHeight;

		int verticalGravityMargin = 0;
		switch ((mGravity & Gravity.VERTICAL_GRAVITY_MASK)	) {
			case Gravity.TOP:
			default:
				break;
			case Gravity.CENTER_VERTICAL:
				verticalGravityMargin = (height - linesSum) / 2;
				break;
			case Gravity.BOTTOM:
				verticalGravityMargin = height - linesSum;
				break;
		}

		int numLines = mLines.size();

		int left;
		int top = getPaddingTop();

		for(int i = 0; i < numLines; i++) {

			lineHeight = mLineHeights.get(i);
			lineViews = mLines.get(i);
			left = mLineMargins.get(i);

			int children = lineViews.size();

			for(int j = 0; j < children; j++) {

				View child = lineViews.get(j);

				if(child.getVisibility() == View.GONE) {
					continue;
				}

				LayoutParams lp = (LayoutParams) child.getLayoutParams();

				// if height is match_parent we need to remeasure child to line height
				if(lp.height == LayoutParams.MATCH_PARENT) {
					int childWidthMode = MeasureSpec.AT_MOST;
					int childWidthSize = lineWidth;

					if(lp.width == LayoutParams.MATCH_PARENT) {
						childWidthMode = MeasureSpec.EXACTLY;
					} else if(lp.width >= 0) {
						childWidthMode = MeasureSpec.EXACTLY;
						childWidthSize = lp.width;
					}

					child.measure(
							MeasureSpec.makeMeasureSpec(childWidthSize, childWidthMode),
							MeasureSpec.makeMeasureSpec(lineHeight - lp.topMargin - lp.bottomMargin, MeasureSpec.EXACTLY)
					);
				}

				int childWidth = child.getMeasuredWidth();
				int childHeight = child.getMeasuredHeight();

				int gravityMargin = 0;

				if(Gravity.isVertical(lp.gravity)) {
					switch (lp.gravity) {
						case Gravity.TOP:
						default:
							break;
						case Gravity.CENTER_VERTICAL:
						case Gravity.CENTER:
							gravityMargin = (lineHeight - childHeight - lp.topMargin - lp.bottomMargin) / 2 ;
							break;
						case Gravity.BOTTOM:
							gravityMargin = lineHeight - childHeight - lp.topMargin - lp.bottomMargin;
							break;
					}
				}

				child.layout(left + lp.leftMargin,
						top + lp.topMargin + gravityMargin + verticalGravityMargin,
						left + childWidth + lp.leftMargin,
						top + childHeight + lp.topMargin + gravityMargin + verticalGravityMargin);

				left += childWidth + lp.leftMargin + lp.rightMargin;

			}

			top += lineHeight;
		}

	}

	@Override
	protected LayoutParams generateLayoutParams(ViewGroup.LayoutParams p) {
		return new LayoutParams(p);
	}

    /**
     * {@inheritDoc}
     */
	@Override
	public LayoutParams generateLayoutParams(AttributeSet attrs) {
		return new LayoutParams(getContext(), attrs);
	}

    /**
     * {@inheritDoc}
     */
	@Override
	protected LayoutParams generateDefaultLayoutParams() {
		return new LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT);
	}

	@TargetApi(Build.VERSION_CODES.ICE_CREAM_SANDWICH)
    public void setGravity(int gravity) {
		if(mGravity != gravity) {
			if((gravity & Gravity.RELATIVE_HORIZONTAL_GRAVITY_MASK) == 0) {
				gravity |= isIcs() ? Gravity.START : Gravity.LEFT;
			}

			if((gravity & Gravity.VERTICAL_GRAVITY_MASK) == 0) {
				gravity |= Gravity.TOP;
			}

			mGravity = gravity;
			requestLayout();
		}
	}

    public int getGravity() {
        return mGravity;
    }

    /**
     * @return <code>true</code> if device is running ICS or grater version of Android.
     */
    private static boolean isIcs() {
        return Build.VERSION.SDK_INT >= Build.VERSION_CODES.ICE_CREAM_SANDWICH;
    }

	public static class LayoutParams extends MarginLayoutParams {

		public int gravity = -1;

		public LayoutParams(Context c, AttributeSet attrs) {
			super(c, attrs);

			TypedArray a = c.obtainStyledAttributes(attrs, R.styleable.FlowLayout_Layout);

            try {
                gravity = a.getInt(R.styleable.FlowLayout_Layout_android_layout_gravity, -1);
            } finally {
                a.recycle();
            }
		}

		public LayoutParams(int width, int height) {
			super(width, height);
		}

		public LayoutParams(ViewGroup.LayoutParams source) {
			super(source);
		}

	}

}
